Update perlfaq4.pod

Marpa::XS is obsolete.  Marpa::R2 is the current stable, supported version of Marpa.
Merge pull request #49 from jeffreykegler/people/kegler/r2

Update perlfaq4.pod
Update perlfaq6.pod
Merge pull request #50 from darfich/master

Update perlfaq6.pod
Fix code examples typos - FH→$fh.

See:

* https://github.com/perl-doc-cats/perlfaq/issues/52

* https://rt.perl.org/Public/Bug/Display.html?id=122923 .
replace use of File::Slurp with Path::Tiny

https://github.com/perl-doc-cats/perlfaq/issues/51
tighten up entries
omit [ExtraTests] from [@Basic]
switch off of deprecated [NoTabsTests]
properly specify when this dist entered core
changelog entries since last release
format all changelog timestamps as ISO8601
add timestamps to Changes for release
add contributors to metadata
tag and push on release; perform git sanity checks before release; commit LICENSE to repository for github
Template::Toolkit is not indexed - Template is
automatically calculate $VERSION
put something in t/, to keep CPANTS happy
more CPANTS mollification
spelling